Mechanisms of adaption to salinity stress in marine gastropods Littorina saxatilis: a proteomic analysis

Salinity is one of the most important abiotic environmental factors for marine animals. If salinity deviates from optimum, adaptive mechanisms switch on to maintain organism’s physiological activity. In this study the proteome of the marine snails Littorina saxatilis from natural habitats (12, 23 and 32‰ and in response to experimental salinity decreasing (from 20‰ to 10‰) was analyzed. The isolation of all snails inside their shells and gradually declining mortality was observed under an acute experimental salinity decrease. Proteomic changes were evaluated in the survived experimental mollusks compared to control individuals using differential 2D gel-electrophoresis (DIGE) and subsequent LC-MS/MS-identification of proteins. Approximately 10% of analyzed proteins underwent upor down regulation during the experiment. Proteins of folding, antioxidant response, intercellular matrix, and metabolic enzymes were identified among them. Proteomic changes observed in experimental hypoosmotic stress partially reproduced in the proteomes of molluscs that live in conditions of natural freshening (estuaries). Possible mechanisms involved in the adaptation process of L. saxatilis individuals to hypoosmotic stress are discussed.